Pneumatic tools are commonly used in the construction industry. In particular, pneumatic nailers are regularly used in roofing and framing projects. In a standard setting, a pneumatic nailer is coupled to a source of high pressure air, e.g., a portable compressor, to supply the pneumatic nailer with a source of pressure regulated compressed air. The pneumatic nailer is usually equipped with an elongated magazine that holds a plurality of nails. The nails are usually available in strips, whereby the nails are uniformly spaced apart from each other and are loosely connected to each other by a clip made from a thin layer of plastic or paper, or are simply connected to each other by a resin-type material. In another form, the nails are provided in a coil that is insertable into a round magazine. Once a worker at the construction site places a strip of nails into the magazine and couples the nailer to the high pressure source, the nailer is ready for operation.
The pneumatic nailer is equipped with an ejector assembly which includes a spring loaded safety tip. A nail from the strip of nails that is placed inside the magazine is internally situated adjacent to the tip of the ejector assembly. The operator places the tip of the ejector assembly against a workpiece to depress the tip. Once the tip is depressed, the nailer becomes responsive to force applied to a trigger. When force is applied to the trigger by the operator, the nailer activates a pneumatic actuating mechanism inside the nailer. The pneumatic actuating mechanism includes a ramming member which is plunged at a high velocity toward the nail from a ready position. The ramming member strikes the nail causing the nail to disengage from the strip of nails, exit through the ejector assembly, and drive into the workpiece. Once the operator releases the trigger, the pneumatic actuating mechanism quickly returns the ramming member to the ready position, and remains there until force is again applied to the trigger by the operator.
During the above operation, the nailers of the prior art provide compressed air to several chambers in order to activate the actuating mechanism as well as to return the actuating mechanism to its ready position. The compressed air is often released to atmosphere after it has performed its intended purpose, e.g., activate the actuating mechanism or return the ramming member. Therefore, several volumes of compressed air perform mechanical work in respective chambers, before being released to atmosphere. As a result, the compressed air leads to power cycling of the compressor, which not only uses power but also shortens the life of the compressor. In addition, some prior art nailers include return mechanisms which are relatively slow to return the ramming member to its ready position. This results in slower tool speed.
Therefore, there is a need for a pneumatic nailer that can recycle compressed air for performing some of its functions during activation of its actuating mechanism and returning the actuating mechanism to the ready position responsive to the worker pulling and releasing the trigger. There is also a need to improve the speed at which the ramming member is returned to the ready position, which would result in faster tool speed.